#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

static bool stop = false;

static void handle_term(int sig) {
    stop = true;
}

int main(int argc, char **argv) {
    signal(SIGTERM, handle_term);   // 捕捉软件终止信号后调用一个返回 void 的函数
    if (argc <= 3) {
        printf("usage: %s ip_address port_number backlog\n", basename(argv[0]));
        return 1;
    }
    const char *ip = argv[1];
    int port = atoi(argv[2]);   
    int backlog = atoi(argv[3]);
    int sock = socket(PF_INET, SOCK_STREAM, 0); // 对应 IPv4 协议 和使用 流服务
    assert(sock >= 0);  // 通过宏对数据进行运行时检查，测试时启用，发布时可以在引入 assert.h 之前 define NDEBUG 关闭 ；好像程序大了的话会明显延长编译时间

    struct sockaddr_in address;     // include <netinet/in.h>
    bzero(&address, sizeof(address));
    address.sin_family = AF_INET;
    inet_pton(AF_INET, ip, &address.sin_addr);  // include <arpa/inet.h>  相关的转换函数
    address.sin_port = htons(port); // include <netinet/in.h>
    
    int ret = bind(sock, (struct sockaddr*) &address, sizeof(address));
    assert(ret != -1);

    ret = listen(sock, backlog);
    assert(ret != -1);

    while (!stop) {
        sleep(1);
    }

    close(sock);
    return 0;
}